#include #include #include #include #include #include #include #include #include #include #include "internal.h" static const struct proc_ns_operations *ns_entries[] = { #ifdef CONFIG_NET_NS &netns_operations, #endif #ifdef CONFIG_UTS_NS &utsns_operations, #endif #ifdef CONFIG_IPC_NS &ipcns_operations, #endif #ifdef CONFIG_PID_NS &pidns_operations, #endif #ifdef CONFIG_USER_NS &userns_operations, #endif &mntns_operations, #ifdef CONFIG_CGROUPS &cgroupns_operations, #endif }; static const char *proc_ns_get_link(struct dentry *dentry, struct inode *inode, struct delayed_call *done) { const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops; struct task_struct *task; struct path ns_path; void *error = ERR_PTR(-EACCES); if (!dentry) return ERR_PTR(-ECHILD); task = get_proc_task(inode); if (!task) return error; if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) { error = ns_get_path(&ns_path, task, ns_ops); if (!error) nd_jump_link(&ns_path); } put_task_struct(task); return error; } static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int buflen) { struct inode *inode = d_inode(dentry); const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops; struct task_struct *task; char name[50]; int res = -EACCES; task = get_proc_task(inode); if (!task) return res; if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) { res = ns_get_name(name, sizeof(name), task, ns_ops); if (res >= 0) res = readlink_copy(buffer, buflen, name); } put_task_struct(task); return res; } static const struct inode_operations proc_ns_link_inode_operations = { .readlink = proc_ns_readlink, .get_link = proc_ns_get_link, .setattr = proc_setattr, }; static int proc_ns_instantiate(struct inode *dir, struct dentry *dentry, struct task_struct *task, const void *ptr) { const struct proc_ns_operations *ns_ops = ptr; struct inode *inode; struct proc_inode *ei; inode = proc_pid_make_inode(dir->i_sb, task, S_IFLNK | S_IRWXUGO); if (!inode) goto out; ei = PROC_I(inode); inode->i_op = &proc_ns_link_inode_operations; ei->ns_ops = ns_ops; d_set_d_op(dentry, &pid_dentry_operations); d_add(dentry, inode); /* Close the race of the process dying before we return the dentry */ if (pid_revalidate(dentry, 0)) return 0; out: return -ENOENT; } static int proc_ns_dir_readdir(struct file *file, struct dir_context *ctx) { struct task_struct *task = get_proc_task(file_inode(file)); const struct proc_ns_operations **entry, **last; if (!task) return -ENOENT; if (!dir_emit_dots(file, ctx)) goto out; if (ctx->pos >= 2 + ARRAY_SIZE(ns_entries)) goto out; entry = ns_entries + (ctx->pos - 2); last = &ns_entries[ARRAY_SIZE(ns_entries) - 1]; while (entry <= last) { const struct proc_ns_operations *ops = *entry; if (!proc_fill_cache(file, ctx, ops->name, strlen(ops->name), proc_ns_instantiate, task, ops)) break; ctx->pos++; entry++; } out: put_task_struct(task); return 0; } const struct file_operations proc_ns_dir_operations = { .read = generic_read_dir, .iterate_shared = proc_ns_dir_readdir, .llseek = generic_file_llseek, }; static struct dentry *proc_ns_dir_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) { int error; struct task_struct *task = get_proc_task(dir); const struct proc_ns_operations **entry, **last; unsigned int len = dentry->d_name.len; error = -ENOENT; if (!task) goto out_no_task; last = &ns_entries[ARRAY_SIZE(ns_entries)]; for (entry = ns_entries; entry < last; entry++) { if (strlen((*entry)->name) != len) continue; if (!memcmp(dentry->d_name.name, (*entry)->name, len)) break; } if (entry == last) goto out; error = proc_ns_instantiate(dir, dentry, task, *entry); out: put_task_struct(task); out_no_task: return ERR_PTR(error); } const struct inode_operations proc_ns_dir_inode_operations = { .lookup = proc_ns_dir_lookup, .getattr = pid_getattr, .setattr = proc_setattr, }; '0' selected='selected'>includemode:
authorLinus Torvalds <torvalds@linux-foundation.org>2017-01-29 13:50:06 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-01-29 13:50:06 -0800
commit39cb2c9a316e77f6dfba96c543e55b6672d5a37e (patch)
tree98fe974ee4e20121253de7f61fc8d01bdb3821c1 /drivers/usb/phy/phy-isp1301.c
parent2c5d9555d6d937966d79d4c6529a5f7b9206e405 (diff)
drm/i915: Check for NULL i915_vma in intel_unpin_fb_obj()
I've seen this trigger twice now, where the i915_gem_object_to_ggtt() call in intel_unpin_fb_obj() returns NULL, resulting in an oops immediately afterwards as the (inlined) call to i915_vma_unpin_fence() tries to dereference it. It seems to be some race condition where the object is going away at shutdown time, since both times happened when shutting down the X server. The call chains were different: - VT ioctl(KDSETMODE, KD_TEXT): intel_cleanup_plane_fb+0x5b/0xa0 [i915] drm_atomic_helper_cleanup_planes+0x6f/0x90 [drm_kms_helper] intel_atomic_commit_tail+0x749/0xfe0 [i915] intel_atomic_commit+0x3cb/0x4f0 [i915] drm_atomic_commit+0x4b/0x50 [drm] restore_fbdev_mode+0x14c/0x2a0 [drm_kms_helper] drm_fb_helper_restore_fbdev_mode_unlocked+0x34/0x80 [drm_kms_helper] drm_fb_helper_set_par+0x2d/0x60 [drm_kms_helper] intel_fbdev_set_par+0x18/0x70 [i915] fb_set_var+0x236/0x460 fbcon_blank+0x30f/0x350 do_unblank_screen+0xd2/0x1a0 vt_ioctl+0x507/0x12a0 tty_ioctl+0x355/0xc30 do_vfs_ioctl+0xa3/0x5e0 SyS_ioctl+0x79/0x90 entry_SYSCALL_64_fastpath+0x13/0x94 - i915 unpin_work workqueue: intel_unpin_work_fn+0x58/0x140 [i915] process_one_work+0x1f1/0x480 worker_thread+0x48/0x4d0 kthread+0x101/0x140 and this patch purely papers over the issue by adding a NULL pointer check and a WARN_ON_ONCE() to avoid the oops that would then generally make the machine unresponsive. Other callers of i915_gem_object_to_ggtt() seem to also check for the returned pointer being NULL and warn about it, so this clearly has happened before in other places. [ Reported it originally to the i915 developers on Jan 8, applying the ugly workaround on my own now after triggering the problem for the second time with no feedback. This is likely to be the same bug reported as https://bugs.freedesktop.org/show_bug.cgi?id=98829 https://bugs.freedesktop.org/show_bug.cgi?id=99134 which has a patch for the underlying problem, but it hasn't gotten to me, so I'm applying the workaround. ] Cc: Daniel Vetter <daniel.vetter@intel.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Imre Deak <imre.deak@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/usb/phy/phy-isp1301.c')